Colloidal metals precursor compound thermal decomposition

It was shown in [5 3,54] that there are two methods to fabricate the homogeneous polymer-immobilized dispersions of colloidal metal particles (Fe, Co, Cr, Mo, W, Mn, Re, Ni, Pd, Pt, Ru, Rh, Os, Ir) using the precursors thermal decomposition. In the former case an active polymer solution (containing amino-, amido-, imino-, nitrilo-, hydroxy-, and other functional groups) is used. In an inert solvent a labile metal compound is gradually added to the solution (this operation creates the favorable conditions for the chemisorption interaction) followed by the suspension thermal decomposition at 370-440 K or by radiation. 

These normally utilize the low- and medium-temperature decomposition of inorganic aluminum salts and hydroxides, or metal-organic compounds of aluminum. Typical precursors include aluminum nitrate and aluminum hydroxides. Hydro-thermal conditions are often applied [8], but colloidal methods (sol-gel) have been extensively studied over the past three decades [9-11]. Recent efforts have been aimed at reducing the particle size of a-Al203, and decreasing the temperature of formation of a-Al203 from transient aluminas to <1000 °C [12]. Results similar to those in sol-gel can be achieved with the use of metal ion-polymer-based precursor solutions. Here, the precursor solution (e.g., nitrate salt) is mixed with a water-soluble polymer, which provides a matrix for the dispersion of cations [13]. 

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